In article <EDSTROM.93Oct14091639 at elmer.hsc.ucalgary.ca>,
John Edstrom <edstrom at elmer.hsc.ucalgary.ca> wrote:
>birds (there's a parthenogenic turkey farm in New Jersey)
HUH?? Are you sure this is right?
One tricky thing with birds is that the females are heterogametic (XY)
and the males are homogametic (XX), the opposite of mammals. So if
parthenogenesis really happens...if an X egg develops
parthenogenetically, you end up with an XX male, who cannot create eggs,
and you stop right there. If a Y egg develops parthenogenetically, you
end up with a YY embryo, which dies.
So are you sure about the turkeys, or could it be some other phenomenon
you are thinking of? Sex-change has very rarely been observed in birds
-- it was either in chickens or turkeys -- but I don't think the gametes
of a sex-changed individual could be completely normal. Let's see, if
you had a female who sex-changed to become a male, and she produced X and
Y sperm, and she mated with a normal XY female, and her sperm were
functional, you'd get 1/4 XX males, 1/2 XY females, 1/4 YY dead eggs.
Hmm. I suppose it's conceivable. But I doubt her sperm would be normal
in the first place. Hmm. Clearly I have to go read up on this.